Adding Vagrantfile and update to tox.ini to fix tox env

- Adding Vagrantfile with necessary package installation steps to allow
  dev environment to be brought up with all necessary OS packages
- modified tox.ini to allow installation of pip modules from external
  source
- fix all flake8 issues
- added .testr.conf to satisfy tox testing requirements
- added simple unit test to fix gate
- fix docs build

Co-Authored-By: Vipul Sabhaya <vipuls@gmail.com>
Change-Id: Ifca9e5c483adb688546a76368d9b821da7371829